1 files changed, 55 insertions, 0 deletions
diff --git a/core/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/StructuredParameterProvider.java b/core/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/StructuredParameterProvider.java
new file mode 100644
index 0000000..decf937
--- /dev/null
+++ b/core/src/main/java/eu/mulk/quarkus/googlecloud/jsonlogging/StructuredParameterProvider.java
@@ -0,0 +1,55 @@
+package eu.mulk.quarkus.googlecloud.jsonlogging;
+
+/**
+ * A user-supplied provider for {@link StructuredParameter}s.
+ *
+ * <p>Instances of this interface that are registered with the {@link Formatter} are applied to each
+ * log entry that is logged.
+ *
+ * <p>If you are using the Quarkus extension, any CDI beans registered under this interface are
+ * registered automatically.
+ *
+ * <p><strong>Example:</strong>
+ *
+ * <pre>{@code
+ * @Singleton
+ * @Unremovable
+ * public final class TraceLogParameterProvider implements StructuredParameterProvider {
+ *
+ *   @Override
+ *   public StructuredParameter getParameter() {
+ *     var b = Json.createObjectBuilder();
+ *     b.add("traceId", Span.current().getSpanContext().getTraceId());
+ *     b.add("spanId", Span.current().getSpanContext().getSpanId());
+ *     return () -> b;
+ *   }
+ * }
+ * }</pre>
+ *
+ * Result:
+ *
+ * <pre>{@code
+ * {
+ *   "jsonPayload": {
+ *     "message": "Request rejected: unauthorized.",
+ *     "traceId": "39f9a49a9567a8bd7087b708f8932550",
+ *     "spanId": "c7431b14630b633d"
+ *   }
+ * }
+ * }</pre>
+ *
+ * @see LabelProvider
+ */
+public interface StructuredParameterProvider {
+
+  /**
+   * Provides a {@link StructuredParameter} to add to each log entry that is logged.
+   *
+   * <p>It is often useful to return a custom {@link StructuredParameter} rather than a {@link
+   * KeyValueParameter} from this method. This way multiple key–value pairs can be generated by a
+   * single invocation.
+   *
+   * @return a {@link StructuredParameter} to add to each log entry that is logged.
+   */
+  StructuredParameter getParameter();
+}